rpm

rpm -qpl kernel-2.4.20-18.10.1.i686.rpm
rpm -qpl ftp://ftp.redhat.com/pub/redhat/RPMS/foo-1.0-1.i386.rpm

List files in RPM file. This command allows you to query a
(possibly) uninstalled RPM file with the use of the the "-p" option.

rpm -qa | grep an installed rpm can be searched

rpm -qa gives the name of the rpm package the file is part of